The present invention relates to a method of manufacturing an ultrasonic probe, the ultrasonic probe and an ultrasonic imaging apparatus. More particularly, the present invention relates to a method of manufacturing an ultrasonic probe exploiting ultrasonic vibration based on the electromechanical coupling coefficient k.sub.31, the ultrasonic probe and an ultrasonic imaging apparatus using such an ultrasonic probe.
When a subject is scanned by ultrasound and the inside of the subject is imaged based on received echo signals, an ultrasonic probe is used to transmit the ultrasound and receive the echo. The ultrasonic probe has an array of ultrasonic transducers. The ultrasonic transducers are conventionally constructed from piezoelectric ceramic.
The individual ultrasonic transducers are provided with electrodes on the front and rear surfaces of the piezoelectric ceramic, and utilizes ultrasonic vibration in which the direction of the electric signal and the direction of mechanical vibration are the same, i.e., ultrasonic vibration based on the electromechanical coupling coefficient k.sub.33.
In order to improve the imaging resolution, the piezoelectric ceramic is formed into a microelement. Accordingly, each ultrasound transducer has a long shape whose height is more than 10 times its base side, and has the electrodes on the upper and lower ends of the long shape.
However, the ultrasonic transducer of such structure has high impedance between the electrodes, making it difficult to attain impedance matching of the driving portion and the receiving portion with the cables used to connect these portions.